|2017 California wildfires|
Smoke from the Alamo and Whittier fires during the 2017 California fire season, on July 8, 2017.
|Total area||1,381,405 acres (5,590.35 km2)|
|Cost||≥$18.0 billion (2018 USD) (Costliest on record)|
|Fatalities||2 firefighters, 45 civilians|
|Non-fatal injuries||12 firefighters, 199 civilians|
The 2017 California wildfire season was the most destructive wildfire season on record, which saw multiple wildfires burning across California. A total of 9,133 fires burned 1,381,405 acres (5,590.35 km2), according to the California Department of Forestry and Fire Protection, including five of the 20 most destructive wildland-urban interface fires in the state's history. Throughout 2017, the fires destroyed or damaged more than 10,000 structures in the state (destroyed 9,470, damaged 810), a higher tally than the previous nine years combined. State data showed that the large wildfires killed 47 people – 45 civilians and 2 firefighters – almost higher than the previous 10 years combined.
Throughout the early months of 2017, there was heavy rainfall over most of California, which triggered widespread flooding, thus temporarily mitigating the state's historic drought conditions. However, according to a report published by the National Interagency Fire Center, the potential for large fires was "expected to remain near normal through the spring, but once fine fuels dry out, there will likely be a spike in grass fire activity.”
In December 2017, strong Santa Ana winds triggered a new round of wildfires, including the massive Thomas Fire in Ventura County. At the time, the Thomas Fire was California's largest modern wildfire, which has since been surpassed by the Mendocino Complex's Ranch Fire in 2018. The December 2017 fires forced over 230,000 people to evacuate, with the 6 largest fires burning over 307,900 acres (1,246 km2) and more than 1,300 structures.
During the year, 5 of the 20 most destructive wildfires in the state's history burned between October and December: #1 Tubbs, #6 Nuns, #7 Thomas, #11 Atlas, and #17 Redwood Valley Complex. The wildfires collectively caused at least $18.0 billion (2018 USD) in damages, including $13.2 billion in insured losses, $3 billion in other economic losses, and $1.8 billion in fire suppression costs, making the 2017 California fires the costliest on record. The total economic cost, including fire suppression, insurance, direct and indirect economic losses, and recovery expenditures is estimated at about $180 billion (2017 USD). This number includes economic harm to the wine industry, where several legacy wineries in Napa and Sonoma were utterly destroyed, and where many wine grapes were severely damaged by smoke. However, the cost to taxpayers, who foot the bill for fire suppression through state and federal taxes, is significant. Cal Fire spent $700 million during fiscal year 2017, far exceeding the approximately $426 million the agency had budgeted that year for fire suppression. This made 2017 the most expensive firefighting year on record in California state history.
According to the National Oceanic and Atmospheric Administration, 2017 will be remembered as a year of extremes. It was the third-warmest year on record for the United States, and it was the second-hottest in California, bringing to the surface the question of long-term climate change and its contribution to the 2017 California fires. The hotter temperatures dry out vegetation, making them easier to burn, predisposing vulnerable regions like California to more wildfires in the coming decades as temperatures continue to rise and rainfall continues to decline.
Climate change is impacting the number and intensity of wildfires Nationwide, particularly in the American West. Although the number of wildfires in California has steadily been declining since 1980, the total acres burned and average acres burned is on the rise. According to Ottmar, the amount of greenhouse gases emitted from a wildfire is directly related to fuel consumption, which is the result of area burned, burning period, fuel characteristics, and fire behavior. These factors lead to the production of greenhouse gases, fine particulate matter emission, black carbon emission, carbon dioxide and monoxide production, as well as other trace gases. The amount and type of emissions resulting from wildfires is dependent on the model used, as demonstrated by Larkin et al. in their comparison of four emissions inventories created for the contiguous United States (CONUS).
California’s forests are huge carbon reservoirs for the state. The forests and vegetation of state wild lands stored an estimated 850 million tons of carbon in 2010, and accounted for approximately 69 million tons of carbon emitted between 2001 and 2010. Annual carbon losses from forests and wild lands in California represent as much as 5 to 7 percent of state carbon emissions from all sectors between 2001 and 2010, according to the study. Wildfires in Southern California burn through fuel sources such as vegetation, gasoline, coal, and create a nasty mixture of aerosols and gases into the atmosphere- include hydrocarbons, nitrogen oxides, and carbon monoxide. Carbon monoxide contributes to reactions that produce ground-level ozone, a harmful pollutant. It can also make breathing difficult to dangerous when trapped near the ground. A 2014 study by Mark Jacobson showed evidence that the burning of biomass like trees, plants, and grass—either by accident or deliberately creates 18 percent of all human-caused carbon emissions (nearly 8.5 billion tons each year), and accounts for 5-10 percent of all air pollution deaths worldwide, or about 250,000 people annually.
According to Jacobson, biomass burning has other impacts that increase warming in the atmosphere, beyond just producing greenhouse gas emissions. The process also creates tiny bits of soot, called black carbon, and traces of harmful substances, known as brown carbon, which together cause more global warming per unit weight than other human-associated carbon sources. California is one of the few jurisdictions in the world to set mandatory greenhouse gas emissions targets. A 2015 study by the National Park Service and UC Berkeley that quantified the amount of carbon stored and released through California forests and wild lands found that wildfires and deforestation are contributing more than expected to the state’s greenhouse gas emissions. These data and the most recent wildfires of 2017 could have dire implications for California’s efforts to meet goals mandated by the state Global Warming Solutions Act, or AB 32, to reduce greenhouse gas emissions to 1990 levels by the year 2020. The bill, which passed in 2006, assumed no net emissions for wild land ecosystems by 2020. Maintenance of balance in carbon storage and emissions is disrupted by wildfires which wipe out vegetation that naturally removes carbon from the atmosphere, exacerbating climate change.
In addition to the tremendous economic loss and danger to human lives, wildfires also play a huge part in significantly worsening air quality in both local and downwind regions, causing more long-term human health problems. Emissions from wildfires transported or nearby urban areas can be a sporadic but significant contribution to urban air pollution. For example, the Environmental Protection Agency's National Emission Inventory reported that 27% of carbon monoxide and 17% of fine particulate matter (below 2.5μm) emissions throughout the Western states was due to wildfires. Smoke generated from wildfires from thousands of miles away can impact air quality in urban areas, and the air pollution generated from the burned biomass can cause these same urban areas to exceed the EPA's National Ambient Air Quality Standards (NAAQS). In addition, increased air pollution due to wildfires can exacerbate pre-existing cardiovascular and respiratory conditions, such as asthma or COPD, and can impair lung function.
Populations most vulnerable to health effects due to wildfires include:
Limiting exposure to wildfire smoke is important for prevention of smoke-related illnesses. Staying indoors, reducing physical activity, using air filters and air conditioners, and reducing other forms of indoor air pollution such as smoking and use of propane and wood burning stoves are strategies to limit exposure to wildfire smoke. In addition, checking the news and local Air Quality Index reports can be useful for information regarding pollution levels and public health safety recommendations for areas impacted by wildfires and wildfire smoke.
Although climate and weather patterns are key drivers of wildfire occurrence across California, humans are currently responsibly for around 95% of wildfires in the state. Many of California's communities are built in or near areas of natural vegetation that is prone to fires. In San Diego alone, 3 out of every 4 homes are built within risk-prone areas. There are a multitude of predictor models that attempt to understand the scope of wildfire activity over the coming century with most agreeing that climate change will have a huge impact on wildfire activity changes, with an estimated increase in total area burned between 15 and 50 percent. Ongoing expansion of communities into fire-prone areas greatly impacts current models developed and must be studied further in order to discern the overall impact on structural damage and lives impacted. California occupies a broad climate space, spanning alpine zones, temperate rain forests, ecosystems, and deserts. In addition, the state is the most populous in the country, meaning that these ever-growing communities will have a large impact on whether or not California will increase or decrease the amount of fires over the course of the next century.
Although it is very difficult to predict future conditions for wildfires in California, several studies have been published in attempt to show the significant impact wildfires will have across the state and the Western United States. Since it is a mountainous and populous state, California has a unique set of both geographical and meteorological parameters associated with wildfires. Projections of future wildfire activity in southern California are sparse and the few that have been completed are contradictory. In addition, projection models differ based on the general circulation models (GCMs) used to estimate changes in wildfire activity. However, a recent study conducted in 2014 by Yue et. al attempted to better estimate and avoid the discrepancies in past wildfire activity projection models. In this study, researchers found that wildfire activity will increase in southwestern California and the Sierra Nevada in coming decades as a consequence of increasing surface temperature.
In 2014, a study found a human fingerprint in growing California wildfire risks. The paper is titled “Extreme fire season in California: A glimpse into the future?” It was published as the second chapter of “Explaining Extreme Events of 2014” by the American Meteorological Society. The authors also projected increases in the drought index, the area under extreme threat of fires, and the days of fire danger, stating that, "The increase in extreme fire risk is expected within the coming decade to exceed that of natural variability and this serves as an indication that anthropogenic climate warming will likely play a significant role in influence California’s fire season."
According to Romps et. al, as annual temperatures and precipitation activity changes due to global warming, there will be increases in lightning strikes across the United States. Per °C of increased temperature due to global warming, there will be a mean increase in lightning strikes of 12 ± 5 percent. This increase in lightning strikes will impact areas like California that have already been impacted by intense wildfire activity. These increases in lightning strikes will increase wildfires caused by natural causes instead of man-made wildfires in less inhabited regions, leading to fires that are difficult for firefighters to reach, leading to larger, more destructive burn areas. In 2015, fires started by electrical lines and equipment burned more acres in California than any other cause. Power lines sparked fires that set records in New Mexico and fed a blaze in Great Smoky Mountains National Park that entered the city of Gatlinburg, Tennessee, and killed 14 people in 2016. In recent years, they have consistently been among the three major causes of California wildfires.
In 2017, a study projected that the single largest threat to Los Angeles County hospitals related to climate change is the direct impacts resulting from the expected increase in wildfires. In Los Angeles County, 34% of hospitals are within one mile of very high fire hazard severity zones, with 24% of these hospitals having a disproportionate share of patient load and 12% impacted by health care shortages. In addition, one of the hospitals studied was in danger of sea-coastal flooding due to the effects of climate change. This issue will become a greater obstacle as sea levels rise due to increase annual temperatures.
As a consequence of further global warming, it is projected that there will be an increase in risk due to climate-driven wildfires in the coming decades. Because of warming, frequent droughts, and the legacy of past land management and expansion of residential areas, both people and the ecology with which we coexist are more vulnerable to wildfires. Wildfire activity is closely tied to temperature and drought over time. Globally, the length of the fire season increased by nearly 19% from 1979 to 2013, with significantly longer seasons in the western states. Since 1985, more than 50% of the wildfire area burned in the western United States can be attributed to anthropogenic climate change. In addition, due to human fire suppression methods, there is a build of fuels in some ecosystems, making them more vulnerable to wildfires. There is greater risk of fires occurring in denser, dryer forests where histrionically these fires occurred in low-density areas. Lastly, with increases in human population, we have expanded out communities into areas that are at higher risk to wildfire threat, making these same populations more vulnerable to structural damage and death due to wildfires. Since 1990, the average annual number of homes lost to wildfires has increased by 300%. Almost 900,000 of western US residences are currently in high risk wildfire areas with nearly 35% of wildfires in California starting within this high risk areas. Thus, policies must be generated that allow for adaptation to increased wildfire risk and reduce further vulnerability in these high risk areas.
This section contains a maps of the locations and burn areas of the fires that occurred during the largest outbreaks of the season. The burn areas of some major fires are included in some of the maps.
|Location of the California wildfires in October 2017|
|Location of the California wildfires in December 2017|
|Name||County||Acres||Start Date||Containment Date||Notes||Ref|
|Jayne||Fresno||5,738||April 20, 2017||April 21, 2017|||
|Opera||Riverside||1,350||April 30, 2017||May 2, 2017|||
|Elm||Fresno||10,345||May 18, 2017||May 21, 2017|||
|Gate||San Diego||2,056||May 20, 2017||May 23, 2017|||
|Oakwood||Madera||1,431||June 10, 2017||June 13, 2017|||
|Highway||Kern||1,522||June 18, 2017||June 28, 2017|||
|Holcomb||San Bernardino||1,503||June 19, 2017||June 29, 2017|||
|Schaeffer||Tulare||16,031||June 24, 2017||August 10, 2017|||
|Salmon August Complex||Siskiyou||65,888||June 25, 2017||December 8, 2017|||
|Manzanita||Riverside||6,309||June 26, 2017||June 30, 2017|||
|Hill||San Luis Obispo||1,598||June 26, 2017||June 30, 2017||50 homes destroyed|||
|Winters||Yolo||2,269||July 6, 2017||July 12, 2017|||
|Alamo||San Luis Obispo||28,687||July 6, 2017||July 19, 2017||1 home destroyed, 1 damaged|||
|Wall||Butte||6,033||July 7, 2017||July 17, 2017||41 homes, 48 outbuildings destroyed, 10 damaged|||
|Whittier||Santa Barbara||18,430||July 8, 2017||October 5, 2017||16 homes, 30 outbuildings destroyed, 7 damaged|||
|Parkfield||Monterey||1,816||July 8, 2017||July 11, 2017|||
|Garza||Fresno||48,889||July 9, 2017||July 21, 2017||1 structure destroyed|||
|Long Valley||Lassen||83,733||July 11, 2017||July 21, 2017|||
|Detwiler||Mariposa||81,826||July 16, 2017||August 24, 2017||63 homes, 68 structures destroyed (131 total), 21 damaged|||
|Modoc July Complex||Modoc||83,120||July 24, 2017||August 16, 2017|||
|Orleans Complex||Siskiyou||27,276||July 25, 2017||September 26, 2017|||
|Empire||Mariposa||6,370||August 1, 2017||November 27, 2017|||
|Parker 2||Modoc||7,697||August 3, 2017||August 29, 2017|||
|Young||Siskiyou||2,500||August 7, 2017||August 28, 2017||Merged into the Eclipse Complex's Oak fire|||
|South Fork||Mariposa||7,000||August 13, 2017||November 27, 2017|||
|Blaine||Riverside||1,044||August 13, 2017||August 16, 2017|||
|Eclipse Complex||Siskiyou||78,698||August 15, 2017||November 29, 2017|||
|Pier||Tulare||36,556||August 29, 2017||November 29, 2017|||
|Railroad||Madera||12,407||August 29, 2017||October 24, 2017||5 homes, 9 structures destroyed|||
|Ponderosa||Butte||4,016||August 29, 2017||September 9, 2017||32 homes, 22 outbuildings, 15 damaged|||
|Mud||Lassen||6,042||August 29, 2017||September 1, 2017|||
|Slinkard||Mono||8,925||August 29, 2017||September 12, 2017|||
|Helena||Trinity||21,846||August 30, 2017||November 15, 2017||133 structures destroyed|||
|Rouse||Riverside||14||August 30, 2017||August 30, 2017|||
|La Tuna||Los Angeles||7,194||September 1, 2017||September 9, 2017||5 homes, 5 structures destroyed|||
|Palmer||Riverside||3,874||September 2, 2017||September 6, 2017|||
|Mission||Madera||1,035||September 3, 2017||September 13, 2017||4 structures destroyed|||
|Buck||Trinity||13,417||September 12, 2017||November 20, 2017|||
|Lion||Tulare||18,900||September 24, 2017||December 2, 2017|||
|Canyon||Riverside||2,662||September 25, 2017||October 4, 2017||6 structures damaged|||
|Cherokee||Butte||8,417||October 8, 2017||October 16, 2017|||
|Atlas||Napa/Solano||51,624||October 8, 2017||October 31, 2017||6 fatalities, 785 structures destroyed, 40 damaged|||
|Tubbs||Napa/Sonoma||36,807||October 8, 2017||October 31, 2017||22 fatalities, 1 injured, 5,643 structures destroyed|||
|Nuns||Sonoma||56,556||October 8, 2017||October 30, 2017||Merged with the Norrbom, Adobe, Partrick, Pressley, and Oakmont Fires. 3 fatalities, 1,200 structures destroyed|||
|Redwood Valley Complex||Mendocino||36,523||October 8, 2017||October 28, 2017||9 fatalities, 43 injured, 545 structures destroyed|||
|La Porte||Butte||6,151||October 9, 2017||October 18, 2017|||
|Cascade||Yuba||9,989||October 9, 2017||October 18, 2017||4 fatalities, 143 residential, 123 outbuildings destroyed|||
|Sulphur||Lake||2,207||October 9, 2017||October 26, 2017||150 structures destroyed|||
|Canyon 2||Orange||9,217||October 9, 2017||October 18, 2017||25 structures destroyed, 55 structures damaged|||
|37||Sonoma||1,660||October 9, 2017||October 13, 2017|||
|Sonoma||17,357||October 9, 2017||October 31, 2017|||
|Lobo||Nevada||821||October 9, 2017||October 18, 2017||At least 30 structures destroyed|||
|Bear||Santa Cruz||391||October 16, 2017||October 27, 2017||7 injuries, 4 structures destroyed|||
|Buffalo Fire||San Diego||1,088||October 17, 2017||November 14, 2017|||
|Tank||Kern||50||October 25, 2017||October 27, 2017|||
|Wildomar||Riverside||866||October 27, 2017||October 29, 2017|||
|Thomas||Ventura/Santa Barbara||281,893||December 4, 2017||January 12, 2018||1,063 structures destroyed, 280 structures damaged, 2 firefighters injured, 1 firefighter and 1 civilian killed|||
|Creek||Los Angeles||15,619||December 5, 2017||January 9, 2018||123 buildings destroyed, 81 buildings damaged, 3 firefighters injured|||
|Rye||Los Angeles||6,049||December 5, 2017||December 12, 2017||6 buildings destroyed, 3 structures damaged, 1 firefighter injured|||
|Little Mountain||San Bernardino||260||December 5, 2017||December 7, 2017||3 injuries|||
|Skirball||Los Angeles||422||December 6, 2017||December 15, 2017||6 structures destroyed, 12 structures damaged, 3 firefighters injured|||
|Lilac||San Diego||4,100||December 7, 2017||December 16, 2017||157 structures destroyed, 64 structures damaged, 3 firefighters and 4 civilians injured|||
|Liberty||Riverside||300||December 7, 2017||December 9, 2017||7 structures destroyed|||
|Range 219||San Diego||100||December 15, 2017||December 15, 2017|||
During the month of October, a series of wildfires broke out throughout Napa, Lake, Sonoma, Mendocino, and Butte counties during severe fire weather conditions, effectively leading to a major red flag warning from much of the northern California area. In the extreme conditions, shortly after the fires ignited, they rapidly grew to become massive conflagrations spanning from 1,000 to well over 20,000 acres apart within a single day. In addition, the fires have destroyed an estimated 8,900+ structures, and killed at least 44 people. The fires burned over 245,000 acres (99,148 ha) of land, and forced over 20,000 people to evacuate.
Multiple wildfires ignited in December across Los Angeles, San Bernardino, Ventura, San Diego, Riverside, Santa Barbara Counties. The fires were exacerbated by unusually powerful and long-lasting Santa Ana winds, as well as large amounts of dry vegetation grown, due to large amounts of precipitation earlier in the year. The fires burned over 307,900 acres (1,246 km2), and caused traffic disruptions, school closures, hazardous air conditions, and massive power outages. California Governor Jerry Brown declared a state of emergency in Ventura and Los Angeles Counties, and Los Angeles Mayor Eric Garcetti declared a state of emergency for the city. The largest fire was the Thomas Fire, which grew to 281,893 acres, becoming California's largest modern wildfire at the time, since surpassed by the Mendocino Complex's Ranch Fire in 2018.
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